Why encode WAV as AAC
AAC gives more quality per kilobit than MP3. At 128 kbps it is close to what MP3 needs 160 to 192 kbps for, and at 256 kbps it is very hard to tell apart from the WAV. That is why Apple Music, YouTube and most streaming services use it. Encoding a WAV master to AAC is therefore a smart way to make compact files that still sound excellent, for example for a website player, a mobile app or a broadcast system that asks for AAC.
Raw AAC or M4A?
This page creates raw .aac files (ADTS streams). They are what some streaming encoders, hardware players and app developers expect. For ordinary listening, M4A is usually more convenient: same codec, but with a container that supports tags and exact seeking. If you plan to play the files in iTunes, the Music app or on an iPhone, use WAV to M4A instead.
Bitrate guide
| Content | AAC bitrate | Size per minute |
|---|---|---|
| Speech, mono | 64 kbps | 0.48 MB |
| Podcast with music | 96 to 128 kbps | 0.7 to 1 MB |
| Music, everyday | 160 to 192 kbps | 1.2 to 1.4 MB |
| Music, high quality | 256 kbps | 1.9 MB |
Compared with about 10.6 MB per minute for CD-quality WAV, even the highest setting saves more than 80 percent.
Things to know
- The AAC encoder works best at 44.1 or 48 kHz. Higher WAV sample rates are converted automatically.
- AAC has a short encoder delay, similar to MP3. For gapless albums, M4A handles this better than raw AAC.
- Raw AAC files carry no tags, so name them carefully.
- Clipping in the WAV stays in the AAC. If your recording is too hot or too quiet, fix it with normalize first.
To compare how different formats affect your material, you can convert one WAV to several formats and listen. For maximum compatibility rather than efficiency, WAV to MP3 remains the safer choice.